One challenge in mixed-signal System-on-Chip (SOC) designs is how to reduce the adverse effects of crosstalk and/or noise coupling among different circuit blocks. The adverse effects of crosstalk/noise coupling in SOC designs may be worse than those in alternative designs that use discrete circuit blocks. Due to the high level of integration in SOC designs, there may be additional crosstalk/noise coupling through power/signal routing, the common silicon substrate, and packaging. These problems may also be exacerbated by the inputs and outputs of SOC circuits.
FIG. 1 illustrates an example of an integrated circuit 104 having a system-on-chip design (an “SOC IC”) that may suffer from cross-talk effects. The SOC IC 104 may include one or more high precision analog-to-digital converter (ADC) 116, interface circuits 108, 122 to interconnect the SOC IC 104 to other integrated circuits and additional processing circuits such as amplifiers 110, correlated differential sampling devices 112, multiplexers 114, interfaces 120 to process and route signals within the SOC IC 104. In the example illustrated in FIG. 1, the SOC IC may accept a large array of input signals IN0-IN255 from a sensor circuit (not shown). A first interface circuit 108 may sample and store the input signals for further processing.
Input amplifiers 110, correlated double sampling (CDS) circuits 112 and multiplexers 114 may route sampled input signals to the ADCs 116 in sequence. The ADCs 116 may convert the routed input signals to digital words, which may be routed further to an output interface 122 via intermediate circuit components (data processor 118 and low-voltage differential signaling (LVDS)/CMOS interface 120) and output from the SOC IC 104.
Electrical activity in the interface circuits and processing circuits 108, 110, 112, 114, 118, 120 and 122 may introduce cross-talk noise into the operation of the ADCs 116. For example, an ADC 116 (say 16 bits of resolution) with a dynamic range of 5 V may need to distinguish between voltage gradations of 76 μV. In large SOC IC designs, however, cross-talk noise may induce voltage fluctuations that cause aberrant performance during ADC conversions. Accordingly, there is a need in the art for managing noise events in integrated circuits to minimize corruption to high precision processing systems.